The present invention relates to wireless communications, and more particularly to a method and apparatus for providing access in a cellular communication system.
Wireless mobile telecommunications systems utilize radio signals to exchange information between base transceiver stations and mobile subscribers. Each base transceiver station transmits from an antenna throughout a predetermined area referred to as a cell. In order to provide service to mobile subscribers over a particular geographic region, many cells are positioned over the region or coverage area.
The service area of a cellular communication system is usually divided into cells of various sizes. Within each cell, a plurality of frequencies are allocated to communicate with a mobile subscriber. Each cell usually operates on a different subset of frequencies than neighboring cells to minimize the density of the used spectrum in a particular geographic area.
Because the frequency band allocated for telecommunications is limited, cellular systems may reuse the same frequencies at other cells. Reuse of the same frequencies may cause a mobile subscriber to access the cellular system at a number of cells having the same channel and digital color code. When a mobile subscriber accesses multiple cells, the call may be rejected or the mobile subscriber may receive a busy signal. Furthermore, multiple accesses usually result in resources being unnecessarily allocated to support "phantom" calls.